The invention relates to a cell contact-making system of a motor-vehicle battery module, in particular for an electric or hybrid vehicle, and also to a motor-vehicle battery module.
Electric or hybrid vehicles are increasingly in demand by consumers since people have become more ecologically aware. These motor vehicles have at least one motor-vehicle battery module, which provides the electrical drive energy for the motor vehicle, as the only drive or as an additional drive. A motor-vehicle battery module usually has a plurality of battery cells which can be, in particular, of prismatic or prism-like design. During production, the battery cells are compressed with distance control and force monitoring, so that they form a battery pack which is held in its defined form by a circumferential frame. In this case, the frame surrounds the battery pack at its sides.
In order to make contact with the individual battery cells and in order to interconnect the battery cells in series, a cell contact-making system is typically provided. The cell contact-making system is arranged on the battery pack in order to make contact with the individual battery cells. The cell contact-making systems known from the prior art have a support board which is of frame-like design and has cutouts in the region of which contact elements of the cell contact-making system are provided in order to make contact with the individual battery cells. The individual contact elements are fastened to the support board, so that the support board is connected to the motor-vehicle battery module by way of the connection of the contact elements to the battery cells. The contact elements are fastened to the support board by way of two of their opposite sides in the region of the cutouts in order to ensure good contact is made with the battery cells, this in turn ensuring good connection of the support board to the motor-vehicle battery module.
Furthermore, the support board typically supports a separate cable channel by which the individual contact elements of the cell contact-making system are electrically coupled to one another in order to form the series circuit. After contact is made with the individual battery cells and said battery cells are interconnected, the cell contact-making system is usually closed by a cover in order to provide electric-shock protection. In this case, the cover is coupled to the support board of the cell contact-making system.
One disadvantage of the known cell contact-making systems and also the known motor-vehicle battery modules has been found to be that the cover and the cell contact-making system are coupled to one another, as a result of which there is a complicated and multi-layered tolerance chain. In this case, the fit of the cover is dependent on the manufacturing tolerances of the cell contact-making system. Furthermore, the motor-vehicle battery module has a correspondingly high number of components, as a result of which, amongst other things, the weight is high and the production process lasts longer, this resulting in higher production costs. Furthermore, it has been found to be disadvantageous that the contact elements are mounted in a fixed manner, as a result of which they cannot yield to an expansion of the battery cells.
The object of the invention is to provide a cell contact-making system, and also a motor-vehicle battery module, which allows simple coupling of the battery cells and, in addition, may be realized in a cost-effective manner.
According to the invention, the object is achieved by a cell contact-making system of a motor-vehicle battery module, in particular for an electric or hybrid vehicle, wherein the cell contact-making system has an, in particular substantially plate-like, support structure and a plurality of separate contact elements, each of which is used to contact two adjacent battery cells of the motor-vehicle battery module. The contact elements are arranged next to one another in a first row, each element being fastened at one side to the support structure.
The basic idea of the invention is to form the cell contact-making system in such a way that the contact elements are at least partially movably mounted, so that the contact elements have a certain degree of play at least in one direction. This is realized by fastening the contact elements on one side. Since they are not fixed on the side opposite the one-sided fastening, they project freely and therefore are movable in principle. Therefore, the contact elements can yield in line with an expansion of the battery cells.
One aspect of the invention provides that the contact elements protrude beyond the edge of the support structure, in particular in such a way that the total width of the support structure with the contact elements fastened to it corresponds to the width of a battery pack which is formed by the battery cells of the motor-vehicle battery module. This creates a compact and lightweight cell contact-making system. This improves the ability to mount the cell contact-making system on the motor-vehicle battery module. Furthermore, the frame which is usually provided can be dispensed with, as a result of which the weight can be reduced and at least one production step can be saved.
In particular, the support structure has a web, which is arranged substantially centrally and runs along the first row, and supporting sections which protrude laterally in relation to the battery cells from said web and which form the edge of the support structure and to which the contact elements are fastened. The support structure of the cell contact-making system is accordingly of particularly simple construction since only the centrally arranged web, which provides the rigidity of the support structure, is provided as a central element. The centrally arranged web can support the cables and also serve to mount the contact elements. The otherwise separate cable channel can be dispensed with, as a result of which the number of components of the cell contact-making system and the weight of said cell contact-making system are reduced.
Furthermore, each supporting section can have a fastening tab to which the respective contact element is fastened. The fastening tabs are arranged on the edge of the support structure where the contact elements are fastened on one side. The fastening tabs can increase the flexibility since they are designed in a bendable manner relative to the substantially rigid web which is arranged centrally, so that the contact elements have even more play.
According to a further aspect of the invention, further contact elements are arranged next to one another in a second row. The further contact elements are provided on a side of the support structure which is opposite the first row, so that contact elements for making contact with in each case two adjacent battery cells of the motor-vehicle battery module are positioned on both sides of the support structure, in particular wherein the contact elements of the first and of the second row are arranged offset in relation to one another by half the width of a contact element in the row direction. The second row likewise extends substantially parallel to the centrally arranged web. Furthermore, the prismatic battery cells, in particular, are interconnected in series as a result since the contact elements which are positioned in such a way that they connect the individual battery cells of the battery pack in series are arranged on the respective end sides of the battery cells.
The object of the invention is further achieved by a motor-vehicle battery module, in particular for an electric or a hybrid vehicle, comprising at least two, in particular prismatic, battery cells which are situated flat next to one another and form a battery pack. The module includes a module frame which circumferentially surrounds the at least two battery cells, and also including a cell contact-making system of the above-described type. The motor-vehicle battery module can be mounted in a simple manner since the cell contact-making system can be fitted to the motor-vehicle battery module more easily on account of the lower number of components and the compact design. Furthermore, fewer tools have to be used, as a result of which production is generally simplified.
In particular, a cover is provided. The cover covers the cell contact-making system and is fastened, for example, to the module frame. The cover constitutes an electric-shock protection device for the cell contact-making system. Since the cover is fastened to the module frame, the cover is decoupled from the cell contact-making system, as a result of which the tolerance chain is also decoupled. Therefore, the tolerance chain is interrupted earlier.
Furthermore, the object is achieved by a motor-vehicle battery module, in particular for an electric or a hybrid vehicle, comprising at least two, in particular prismatic, battery cells which are situated flat next to one another and form a battery pack. The module includes a module frame which circumferentially surrounds the at least two battery cells. The module further includes a cell contact-making system which electrically connects the battery cells of the motor-vehicle battery module to one another, and also includes a cover which is separate from the cell contact-making system, covers the cell contact-making system and is fastened to the module frame, in particular is latched to the module frame. The cover is decoupled from the cell contact-making system, so that the tolerance chain is decoupled. Accordingly, the tolerances of the cell contact-making system do not have any influence on the fit of the cover, as a result of which the complexity of the motor-vehicle battery module is correspondingly reduced.
According to a further aspect of the invention, the module frame has two pressure plates which bear against opposite sides of the battery pack, and also two tie rods which are connected to the two pressure plates, wherein the cover is fastened to at least one pressure plate and/or to at least one tie rod. As a result, the cover can be mounted on the module frame in a particularly simple manner since the cover is coupled directly to one or all of the elements of the module frame. In particular, the cover can be latched, as a result of which mounting can once again be performed in a simpler and more rapid manner since the connection is formed when the cover is pressed down.
Furthermore, the cover can be in the form of a thermoformed cover and/or can be formed from an electrically insulating material. The high-voltage insulation of the motor-vehicle battery module can be formed or supplemented in this way. Furthermore, the cover can have a small wall thickness, wherein it is produced, in particular, from a plastic, so that weight can further be saved. In general, the air gaps and creepage distances of the insulation can in this way be maintained in a less complex manner owing to the insulating cover which is fitted directly to the insulating module frame.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.